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• Render YUV video in OpenGL of ffmpeg using CVPixelBufferRef and Shaders

  4 septembre 2012, par resident_

  I'm using to render YUV frames of ffmpeg with the iOS 5.0 method "CVOpenGLESTextureCacheCreateTextureFromImage".

  I'm using like the apple example GLCameraRipple

  My result in iPhone screen is this : iPhone Screen

  I need to know I'm doing wrong.

  I put part of my code to find errors.

  ffmpeg configure frames :

  ctx->p_sws_ctx = sws_getContext(ctx->p_video_ctx->width, 
  
                                  ctx->p_video_ctx->height, 
  
                                  ctx->p_video_ctx->pix_fmt, 
  
                                  ctx->p_video_ctx->width, 
  
                                  ctx->p_video_ctx->height,
  
                                  PIX_FMT_YUV420P, SWS_FAST_BILINEAR, NULL, NULL, NULL);
  
  
  
  
  
  // Framebuffer for RGB data
  
  ctx->p_frame_buffer = malloc(avpicture_get_size(PIX_FMT_YUV420P,
  
                                                  ctx->p_video_ctx->width, 
  
                                                  ctx->p_video_ctx->height));
  
  
  
  avpicture_fill((AVPicture*)ctx->p_picture_rgb, ctx->p_frame_buffer,PIX_FMT_YUV420P, 
  
                 ctx->p_video_ctx->width, 
  
                 ctx->p_video_ctx->height);

  My render method :

  if (NULL == videoTextureCache) {
  
      NSLog(@"displayPixelBuffer error");
  
      return;
  
  }    
  
  
  
  
  
  CVPixelBufferRef pixelBuffer;    
  
     CVPixelBufferCreateWithBytes(kCFAllocatorDefault, mTexW, mTexH, kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange, buffer, mFrameW * 3, NULL, 0, NULL, &pixelBuffer);
  
  
  
  
  
  
  
  CVReturn err;    
  
  // Y-plane
  
  glActiveTexture(GL_TEXTURE0);
  
  err = CVOpenGLESTextureCacheCreateTextureFromImage(kCFAllocatorDefault, 
  
                                                     videoTextureCache,
  
                                                     pixelBuffer,
  
                                                     NULL,
  
                                                     GL_TEXTURE_2D,
  
                                                     GL_RED_EXT,
  
                                                     mTexW,
  
                                                     mTexH,
  
                                                     GL_RED_EXT,
  
                                                     GL_UNSIGNED_BYTE,
  
                                                     0,
  
                                                     &_lumaTexture);
  
  if (err) 
  
  {
  
      NSLog(@"Error at CVOpenGLESTextureCacheCreateTextureFromImage %d", err);
  
  }   
  
  
  
  glBindTexture(CVOpenGLESTextureGetTarget(_lumaTexture), CVOpenGLESTextureGetName(_lumaTexture));
  
  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
  
  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);     
  
  
  
  // UV-plane
  
  glActiveTexture(GL_TEXTURE1);
  
  err = CVOpenGLESTextureCacheCreateTextureFromImage(kCFAllocatorDefault, 
  
                                                     videoTextureCache,
  
                                                     pixelBuffer,
  
                                                     NULL,
  
                                                     GL_TEXTURE_2D,
  
                                                     GL_RG_EXT,
  
                                                     mTexW/2,
  
                                                     mTexH/2,
  
                                                     GL_RG_EXT,
  
                                                     GL_UNSIGNED_BYTE,
  
                                                     1,
  
                                                     &_chromaTexture);
  
  if (err) 
  
  {
  
      NSLog(@"Error at CVOpenGLESTextureCacheCreateTextureFromImage %d", err);
  
  }
  
  
  
  glBindTexture(CVOpenGLESTextureGetTarget(_chromaTexture), CVOpenGLESTextureGetName(_chromaTexture));
  
  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
  
  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);     
  
  
  
  glBindFramebuffer(GL_FRAMEBUFFER, defaultFramebuffer);
  
  
  
  // Set the view port to the entire view
  
  glViewport(0, 0, backingWidth, backingHeight);
  
  
  
  static const GLfloat squareVertices[] = {
  
      1.0f, 1.0f,
  
      -1.0f, 1.0f,
  
      1.0f,  -1.0f,
  
      -1.0f,  -1.0f,
  
  };
  
  
  
  GLfloat textureVertices[] = {
  
      1, 1,
  
      1, 0,
  
      0, 1,
  
      0, 0,
  
  };
  
  
  
  // Draw the texture on the screen with OpenGL ES 2
  
  [self renderWithSquareVertices:squareVertices textureVertices:textureVertices];
  
  
  
  
  
  // Flush the CVOpenGLESTexture cache and release the texture
  
  CVOpenGLESTextureCacheFlush(videoTextureCache, 0);    
  
  CVPixelBufferRelease(pixelBuffer);     
  
  
  
   [moviePlayerDelegate bufferDone];

  RenderWithSquareVertices method

      - (void)renderWithSquareVertices:(const GLfloat*)squareVertices textureVertices:(const GLfloat*)textureVertices
  
  {
  
  
  
  
  
    // Use shader program.
  
      glUseProgram(shader.program);
  
  
  
  // Update attribute values.
  
  glVertexAttribPointer(ATTRIB_VERTEX, 2, GL_FLOAT, 0, 0, squareVertices);
  
  glEnableVertexAttribArray(ATTRIB_VERTEX);
  
  glVertexAttribPointer(ATTRIB_TEXTUREPOSITON, 2, GL_FLOAT, 0, 0, textureVertices);
  
  glEnableVertexAttribArray(ATTRIB_TEXTUREPOSITON);
  
  
  
  glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
  
  
  
  // Present
  
  glBindRenderbuffer(GL_RENDERBUFFER, colorRenderbuffer);
  
  [context presentRenderbuffer:GL_RENDERBUFFER];

  }

  My fragment shader :

  uniform sampler2D SamplerY;
  
  uniform sampler2D SamplerUV;
  
  
  
  
  
  varying highp vec2 _texcoord;
  
  
  
  void main()
  
  {
  
  
  
  mediump vec3 yuv;
  
  lowp vec3 rgb;
  
  
  
  yuv.x = texture2D(SamplerY, _texcoord).r;
  
  yuv.yz = texture2D(SamplerUV, _texcoord).rg - vec2(0.5, 0.5);
  
  
  
  // BT.601, which is the standard for SDTV is provided as a reference
  
  
  
  /* rgb = mat3(    1,       1,     1,
  
   0, -.34413, 1.772,
  
   1.402, -.71414,     0) * yuv;*/
  
  
  
  
  
  // Using BT.709 which is the standard for HDTV
  
  rgb = mat3(      1,       1,      1,
  
             0, -.18732, 1.8556,
  
             1.57481, -.46813,      0) * yuv;
  
  
  
     gl_FragColor = vec4(rgb, 1);
  
  
  
  }

  Very thanks,

• is it possible to play h264-mpegts format in ios ?

  11 octobre 2012, par jAckOdE

  Server transcodes the video to the h264/aac, and send video data to client simultaneously. To play and save the video data at the same time, I use mpegts as the container format, but the problem is that ios MediaPlayer can not play mpegts file.

  Google said that i can used ios-build of ffmpeg to do the task, but it seem to be an overkill. is there any other ways to play mpegts in iphone using just iOS SDK ?

• Displaying YUV420 data using Opengles shader is too slow

  28 novembre 2012, par user1278982

  I have a child thread called A to decode video using ffmpeg on iPhone 3GS, another thread called B to display yuv data, in thread B, I used glSubTexImage2D to upload Y U V textures, and then convert yuv data to RGB in shader, but the frame rate in the decode thread is only 15fps.Why ?

  Update :
  The frame size is 720 * 576.
  I also found something interesting that if I didn't start the thread displaying the YUV data, the frame rate calculated in the decode thread is 22 fps,otherwise 15 fps.So I think that my displaying method must be inefficient.the code as below.

  I have a callback in the decode thread :

  typedef struct _DVDVideoPicture
  
  {
  
     char *plane[4];
  
     int iLineSize[4];
  
  }DVDVideoPicture;
  
  
  
  void YUVCallBack(void *pYUVData, void *pContext)
  
  {
  
     VideoView *view = (VideoView *)pContext;
  
     [view.glView copyYUVData:(DVDVideoPicture *)pData];
  
     [view calculateFrameRate];
  
  }

  The copyYUVData method extract the y u v planes separately. The following is displaying thread method.